Abdominal Aortic Aneurysms (AAA) are weakened areas in the aorta that form balloon-like bulges, or sacs, in approximately the abdominal area. As blood flows through the aorta, the pressure of the blood pushes against the weakened wall, causing it to enlarge. Blood pools in the enlarged area, usually without forming a firm clot. AAA is usually the result of degeneration in the media of the arterial wall, resulting in a slow and continuous dilatation of the lumen of the vessel. Ruptured AAA is about the 13th-leading cause of death in the United States, causing an estimated 15,000 deaths per year. While more than 500,000 Americans have been diagnosed with aortic aneurysms, less than 100,000 are treated due to shortcomings of current devices and the risk of open surgical procedures.
Clips and open surgery have been the traditional interventional treatments for AAA. More recently, less invasive techniques have been attempted, such as introducing a coil into the aneurysm that triggers blood clotting. Of those AAA's that are repaired, only about 30,000 procedures are minimally invasive. Other approaches have involved placing endografts across the aneurysm, so that blood can flow through the lumen of the graft and reduce the pressure on the aneurysm wall to prevent its enlargement and rupture. Stents have been used with the endografts to facilitate their placement and stabilize them in the patient. Conventional endograft devices, however, can be a poor fit for aneurysms, which can have complex three-dimensional geometries. Further, aneurysms can change shape over time leading to failure of an implanted graft and/or stent.